


And Then There Were Four

by Aeiouna



Series: The More The Merrier (Poly Ships) [8]
Category: Voltron: Legendary Defender
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe - Modern Setting, Established Relationship, Knotting, Mpreg, Multi, Non-Traditional Alpha/Beta/Omega Dynamics, Polyamory, Threesome, Threesome - M/M/M
Language: English
Status: Completed
Published: 2018-12-29
Updated: 2018-12-29
Packaged: 2019-09-29 15:59:27
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,024
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17206439
Author URL: https://archiveofourown.org/users/Aeiouna/pseuds/Aeiouna
Summary: Based on a prompt given in one of my Voltron Discord servers:Unlike Betas, who can impregnate other Betas on their own, Omegas require two DNA codes from the two types of Alphas. Alphas are split into two categories, Alpha-Thetas and Alpha-Sigmas. Alpha-Thetas are among the more prominent of the Alpha types, while Sigmas are rare and highly revered. As the years progressed organizations cropped up which existed for the express purpose of assisting mated pairs to get pregnant. These Alpha-Sigmas often were not ones to tie themselves to a specific pair, enjoying the ability and freedom to move from partner to partner.Alpha-Sigmas are revered in society as there are so few, and without them both Alphas and Omegas would go extinct.





	And Then There Were Four

**Author's Note:**

  * For [DiamondWinters](https://archiveofourown.org/users/DiamondWinters/gifts).



> Based on a prompt given in one of my Voltron Discord servers:
> 
>  
> 
> _Unlike Betas, who can impregnate other Betas on their own, Omegas require two DNA codes from the two types of Alphas. Alphas are split into two categories, Alpha-Thetas and Alpha-Sigmas. Alpha-Thetas are among the more prominent of the Alpha types, while Sigmas are rare and highly revered. As the years progressed organizations cropped up which existed for the express purpose of assisting mated pairs to get pregnant. These Alpha-Sigmas often were not ones to tie themselves to a specific pair, enjoying the ability and freedom to move from partner to partner._
> 
>  
> 
> _Alpha-Sigmas are revered in society as there are so few, and without them both Alphas and Omegas would go extinct._

"I want a baby."

The seemingly simple phrase caused Shiro to choke on his morning coffee. If Shiro had been paired with any other Omega, this wouldn't have been shocking. Typical Omegas always talked about how they want to be parents. Typical Omegas nested during every heat.

Keith wasn't a typical Omega.

Keith was the type of Omega who appreciated the natural birth control that came with only needing an Alpha Theta to feel satisfied during his heats (and he'd be the first to tell you that Shiro was the best Alpha Theta there ever was). He was the type of Omega that longs for digging his feet in the sand of the beach, not the pitter patter of little feet on their hardwood floors.

And Shiro had been okay with that. As much as he wanted kids, he knew the decision ultimately rested with on Keith. Keith had to go through pregnancy. Keith had to go through childbirth. Shiro couldn't and wouldn't force it on him.

"Shiro, honey?" Keith brought Shiro back to reality. "Hey, you wanna do this with me?"

"God, _yes_!" Shiro wrapped his arms around Keith. "Of course I want to do this with you! Only you!"

"So I guess we should find and Alpha Sigma through one of those services or something?" Keith picked at his breakfast, "Since we need one."

Shiro shook his head. "Nah, I know exactly who I'm going to ask to help us out." And with that he pulled out his phone, dialing a number who knew almost as well as he knew Keith's.

"Hello?" the voice on the other end of the line was groggy, stifling a yawn. Right, it was 8:30am. "Too early" for him.

Him being Shiro's best friend. "Matt! Hey, what's up? It's Shiro!"

"Shiro, you _know_ I don't function before, like, 11am. What are you calling me?"

"Keith wants a baby," Shiro stated.

Matt was suddenly _very_ wide awake. He'd known for a long time that this call was coming, but knowing how Shiro's beloved Omega was, he expected it to come a lot, lot, _lot_ later. "Keith wants a baby?"

"That's what I said," Shiro affirmed, his eyes closing involuntarily as the scent of firewood and cinnamon — Keith's scent — filled the air of their dining room. It always calmed Shiro down, when it didn't damn near bring him into a rut (which is what happened when Keith scented during a heat). "Keith. Wants. A. Baby. And I made a promise to you a long time ago that I intend to keep: I want you to be my — our — Alpha Sigma." He leaned back in his chair, Keith was scenting even harder.

Keith crawled into Shiro's lap and nuzzled his neck, right under Shiro's own scent gland, wanting Shiro's sage and mahogany mixed in the air with his firewood and cinnamon. He loved Shiro, he loved Shiro so much. He had been nervous about mating with with a random alpha, but Matt? Matt he knew. Matt he knew very well. He felt more comfortable about the whole thing knowing it was going to be with two alphas he trusted: his good friend Matt, and his beloved Shiro.

"I'll keep you in the loop about Keith's next heat, we can do it then? If Keith's willing," Shiro looked down at Keith who was nodding furiously. "Okay, that settles it. Keith's next heat, we do this."

\---

Shiro dropped his messenger bag by the door and toed his shoes off. "Keith?" he called. No answer.

But the house reeked of firewood and cinnamon, in the way that made Shiro's cock wake up in his slacks instead of relax him.

Keith was in heat.

Shiro was used to coming home to Keith in heat, walking into their shared bedroom and finding Keith on his hands and knees, presenting his asshole, wet with slick to him by making sure it was facing the door and is right there when Shiro opened it. But that wasn't the scene Shiro walked into this time. Instead, Keith was in the middle of the bed, surrounded by pillows and the entirety of Shiro's dirty clothes hamper that had been upended onto the bed.

Keith was _nesting_.

"Hold on just a few, Firecracker," Shiro cooed, practically ripping his clothes off and crawling into bed with Keith. He then leaned over for his discarded work slacks, his phone in the back pocket. "I just need to call Matt, okay?"

Keith immediately clung to Shiro, whimpering as his body, hotter than usual thanks to his heat, made contact with Shiro's which was quite a bit cooler. "Okay, Moonstone, okay. I hope he gets here quickly."

Shiro ran his fingers of one hand through Keith's sweat drenched locks while he dialed Matt's number with the other.

"Hello?"

"Matt, it's Shiro. Keith is—" he started, but was cut off.

"I'm on my way," was all Matt said before hanging up.

Shiro pulled Keith into his arms. "He's coming, Keith, he's coming." He wished he could help, but for an Omega to be properly impregnated, the Alpha Sigma needed to go first, then the Alpha Theta got their turn (this was why Omegas only needed an Alpha Theta to get through their heats). So they had to wait for Matt.

He soon heard the click of the door unlocking (Matt had long been given a key to Shiro's house) and called from down the hall. "Bedroom, Matt!" He only looks up from Keith when a third combo of scents was added to the air: fresh linen and citrus. Matt _would_ smell like linen and citrus. He motioned for Matt to join them on the bed.

Matt stripped himself of his clothing and crawled into bed with the mated pair. He cradled Keith's cheek in his hand. "Have you taken Shiro's knot before, Keith?"

Keith nodded, gravitating toward Matt. His instinct knew there was an Alpha Sigma in his presence, and his instinct was making him want this Alpha Sigma desperately. "Matt..."

"Can I kiss you?" Matt whispered. He usually never asked. He was usually mating with an Omega as part of his job, as part of his commitment to the species. He never had a connection with the mated pairs he worked with. But he had a history with, a friendship with, and dare he say it — a love for Shiro and Keith. If Alpha Sigmas mated for life, if they were allowed to mate for life, he'd be with these two without question.

Keith nodded again, chasing Matt's lips, sighing softly as their mouths connected. He felt his body be rolled onto its back as Matt pinned him onto the bed. He looked around, finding Shiro had managed to get out of bed and was now standing off to the side watching them. He reached out for Shiro. "Moonstone..."

Matt followed Keith's gaze to Shiro. "Shiro, c'mon, get your ass in this bed with us."

"Alpha Theta stays away until Alpha Sigma is done," Shiro recites, almost a mantra they told Alphas during sex ed in middle school (because that was _exactly_ they told Alphas during sex ed in middle school).

Matt rolls his eyes. "Oh my _God_ Shiro, please. Please get in here, I want this to be a group experience. Besides, your — no our — Omega needs you."

Shiro slowly headed for the bed and laid beside Keith. "Shh Firecracker, I'm here. I'm here." He laid beside Keith and wrapped his arms around him.

Keith released his lips from Matt's once he felt Shiro near him and chased after his mouth instead. Shiro eagerly closes the gap between them.

Matt watched Keith and Shiro interact and he sighed a bit. It's something he noticed with all of the pairs he's bred with, but especially with these two. There's so much love between the pairs he's worked with.

Love that he's long wished for himself.

He shook the thought away and cleared his throat. "Keith, are you ready?"

Keith looked up from where he and Shiro were making out. "Ready?"

Matt lubed up his fingers with the slick leaking from Keith and coated his cock with it. "This."

Keith's eyes widened and he nodded. That meant this was happening. Or did it?

He could always just, refuse to take Shiro's knot after.

No... Keith was doing this. He wanted this. He wanted Matt. He wanted Shiro.

He wanted to have their child.

"Please, Matt, let me take your knot. Then, Shiro, my Moonstone, I want yours," Keith whispered.

"You have us, both of us," Matt leans over Keith as he easily slipped into Keith's slick ass. 

Keith had to look at Shiro for approval but there was nothing but love and adoration in his eyes. "I obviously don't mind."

Matt's thrusts start out methodical, practiced, almost clinical. That is, of course, until Shiro grabs him by the back of his neck and kisses him hard.

That was new. Well, he also kissed Keith which, too, was new.

Everything about this was new.

As soon as Shiro's lips met his, he changed the rhythm in his thrusts. He started enjoying this, enjoying being with Keith. Being with Shiro.

Could he?

Nah, never.

He had trained his body to finish quickly. Finish and let the Alpha Theta take over. But with Keith he never wants it to end.

"Can I take my time?" He looks from Keith to Shiro and they both nod.

"We want you to enjoy yourself too," Shiro says between more kisses. "This isn't like one of your paid gigs."

Matt slows down a bit, starts to learn Keith's likes and dislikes in the bedroom, and in the process a few of his own as well. He didn't know he could actually _enjoy_ being with an Omega.

"Keith," he moaned out. The first time he ever said an Omega's name during sex, "You feel so good."

"So do you Matt," Keith pulled him close, wanting him near. Wanting him close, "Both you and Shiro feel so, _so_ good. And I can't wait to have Shiro's knot after yours."

Matt chuckled at that. "Eager, are you Keith?"

"Keith is always eager for my knot when he's in heat," Shiro answered for Keith. Hopefully, after tonight, Keith would be eager for Matt's as well.

After what felt like both an eternity and not nearly long enough, he felt the coil in his stomach start to snap and his knot start to form inside Keith. And then he came. " _Keith!_ "

He spilled his seed inside Keith, his orgasm coming in waves as he waited for his knot to come down enough to pull out. He pressed kisses along Keith's neck as they stayed together, until Matt could pull out.

"You ready for Shiro?" he asked softly.

Keith nodded and reached for him. "Shiro, baby, please."

Shiro shushed him, crawling on top of Keith. "I gotcha baby, I gotcha."

Shiro doesn't need any preparation, doesn't even need to lube up with Keith's slick. Matt stretched him nice and wide already. "God, I could get used to this, slipping into you like it was nothing, and yet you still clench right around my cock. Fits like a glove."

"Shiro... _Shiro_ ," Keith moaned and Shiro worked his way inside him, "So good... I love you, I love you!"

"I love you too, baby," Shiro found the right spot, the one that turns Keith into mush, over and over again.

"Oh _God_ , Shiro!" Keith clawed at Shiro's back, "So good, so good, so _good_!"

"It's always good with you," Shiro smiled and then looked up at Matt. "C'mere you." He grabbed Matt by the back of the head again and kissed him. "You belong as well."

Keith reached for Shiro. "Shiro... Shiro... I..."

This would normally be where Shiro pumps Keith's cock to finish him off, but instead he nudged Matt. "Why don't you do the honors?"

Matt nodded and smiled as he grabs Keith's cock and gives it only a couple pumps before Keith is coming all over his own stomach, both Matt's and Shiro's names on his lips.

Shiro cried out next, as his knot took over and he was spilling into Keith. 

Matt's instinct now that Keith has taken both him and Shiro is to get up, to leave. He's served his purpose. In a few weeks, Keith will find out he is with child. And while Matt will know of the child as a friend, the child will never know the truth. That's the point.

"Matt?" Shiro stretches, voice raspy from recovering from their previous actions, still buried deep inside Keith as his knot came down. "Why don't you... stay the night?"

Keith stirs, as if Shiro's words awoke him. "Why don't you stay forever?"

"W-what?" Matt didn't know what to say.

"We know it's not conventional, and we understand you can't be exclusive, but," Shiro sat up, situating Matt between the two of them on the bed, "be a triad with us. We both love you so much, and we don't want this to be a situation where we call on you whenever we want to breed."

Keith wrapped his arms around Matt. "You can take turns getting me through my heats, since I only need one alpha to be sated. You can move in with us. We want our babies, the one we conceived today and any future children we have, to know all three of their daddies. _As their daddies._ And you deserve to feel like more than just breeding stock."

Matt couldn't believe what he was hearing. A pair wanted to be with him? And it was his beloved Keith and Shiro at that? "I... Yes! Of course! I love you guys so much!"

"We love you too," Shiro whispered into Matt's neck. "You need a nickname. Moonstone, Firecracker, and..."

"Lemondrop!" Keith said without hesitation, "His scent is of lemon, so he's our Lemondrop!"

"Perfect, Firecracker!" Shiro kissed him deeply, then kissed Matt as well. "I love you, Lemondrop."

"I love you too," Matt whispered. "I love you too, Shi— Moonstone. And I love you, Firecracker."

Shiro and Keith can feel their hearts skipping several beats hearing Matt call them by their pet names.

They couldn't have made a better decision.

* * *

"I want his first name to be Japanese, because he's going to have Shiro's last name," Keith had a highlighter in his mouth and a plethora of printouts of Japanese baby names placed on his growing stomach. He was due at any time, and they still don't have a handle on what they're naming their little boy. "I've already decided on his middle name, but Shiro and I are keeping that a secret until he's born."

Matt leaned over Keith's shoulder, a quick kiss pressed to the junction between Keith's neck and shoulder blade, before finally settling his chin on the shoulder. "What about this one?" and he points to a name.

"Keitaro?" Keith chewed on the highlighter and took a glance at the meaning. " _Blessed, huge gift_. Yeah, that definitely describes our little one." he smiled, rubbing his stomach as the baby responded with a light kick. "I think he likes it as well. Keitaro Shirogane. That has a nice ring to it!"

Matt rubbed his own hand along Keith's stomach. "Hi Keitaro! Your three daddies are itching to meet you!"

They both looked up at the door when they heard it shut and Shiro's voice call out to them, "Wait, did I hear you right? Did you pick out a name?"

When Shiro's head was crooked into Keith's other shoulder the same way Matt's was, Keith nods with a laugh. "Keitaro. It means _blessed_ or _huge gift_. Very fitting of our little man."

Shiro brought his lips close to Keith's ear and smiled as he whispered, "Keitaro Matthew Shirogane" into it.

Keith's grin was a mile wide and he just nods.

"What are you two grinning about?" Matt raised an eyebrow as he watched his partners conspire against him.

"You'll find out when Keitaro is born," Shiro leaned around and kissed Matt. "It's a surprise."

Keith suddenly shifted uncomfortably between them and grimaced. "He might be finding out sooner rather than later. I think Keitaro was just waiting for us to name him before he arrived."

"You mean? Now?" Shiro jumped up and grabbed the hospital bag (which was more like a suitcase, cause while Keith still experienced labor pains, he still would ultimately need a C-section to deliver since male Omegas lacked a birth canal, they only had a womb) while Matt helped Keith up into the car.

The drive to the hospital was uneventful and quiet save for Keith cursing the day he ever suggested to Shiro he wanted a baby.

Shiro wrapped an arm around Matt, who snuggled up into him, while they say in the operating room while Keith's C-section was performed. They both looked up when they heard a piercing infant cry. "He's here!" They got up and walked up to the doctor who asked after they weighed, measured, diapered and swaddled Keitaro, "Who would like to hold him first?"

Shiro turned to Matt, "Babe, you should be the first one to hold our Keitaro Matthew."

The tears that threatened to fall from Matt's eyes finally gave in upon hearing their son's middle name. "His middle name is my name?"

"We thought it fitting," Shiro explained as the doctor placed Keitaro in Matt's arms, "That we name him after his Daddy Matt, since without you, there'd be no him, but we still wanted him to have some sense of self, so we made it his middle name."

"And if we'd had a girl?" Matt asked with a laugh.

"We thought about that," Shiro had a answer for everything, "Matilda. Her middle name would have been Matilda."

Keitaro let out a whimper until Matt started rocking him, walking over to where Keith could see him.

Keith was still a bit groggy from the anesthesia, but was able to manage a, "Welcome to the world, Keitaro Matthew Shirogane."

"You rest now, Firecracker," Matt kissed Keith's temple, "Your Moonstone and Lemondrop have this."

They definitely did.


End file.
